(UAV) has grown rapidly over the past decade. UAV applications range from purely scientific over civil to military. Technical advances in sensor and signal processing technologies enable the design of light weight and economic airborne platform

The modeling and attitude stabilization control problems of a four-rotor vertical takeoff and landing unmanned air vehicle (UAV) known as the quadrotor are investigated.The quadrotor’s attitude is represented by the unit quaternion rather than Eule

CONTROLA OF QUADROTOR USING BACKSTEPPING